Mumps is a common and generally mild viral infection of children. In unvaccinated populations, which include the whole of sub-Saharan Africa, it is one of the main causes of sensorineural deafness and encephalitis. Adults classically present with parotid swelling and up to a quarter of infected men experience orchitis. The MMR vaccine is safe and effective but may lead to an upward shift in the age and severity of presentation if introduced into national immunization programmes without high levels of cover.

Biology

Mumps is caused by a paramyxovirus, a close relative of parainfluenza. It was first recognized by Hippocrates in the fifth century BC when he described an ‘outbreak of swelling about the eyes [where] inflammation seized sometimes one of the testicles’. It is an RNA virus with one distinct serotype and several genetic subtypes. The capsid surface is made up of haemagglutinin-neuraminidase and fusion proteins, which are responsible for cell adhesion and entry.

Epidemiology

Mumps is spread by respiratory droplets and direct contact with contaminated material. It has an incubation period of 16–18 days (range 2–4 weeks) and patients are contagious from 2 days before to 9 days after the onset of parotid swelling.